Possible relationships between steroid-hormone receptors and the diethylstilbestrol (DES)-induced abnormalities of the cervix and vagina will be explored through the examination of the ontogeny of steroid-hormone receptors in these tissues when exposed to different steroid conditions. The quantity of estrogen and progesterone receptors in the cytosol (cRe, cRp) of mice and hamsters will be determined by Scatchard plot analysis; nuclear estrogen and progesterone receptors (nRe, nRp) will be measured by exchange assays. These receptors will also be characterized by sucrose-glycerol density gradients and competitive binding studies. The above receptor parameters will be measured during the ontogeny of the cervix and vagina in (1) normal, (2) vehicle-treated, (3) DES-treated, (4) ovariectomized and/or adrenalectomized and (5) progesterone-treated animals. The underlying hypothesis is that DES, when administered during early developmental stages, alters the quantity or binding qualities of Re and/or Rp and the hormone receptor-nuclear acceptor interactions in the cervix and vagina at later times.